1. Field of the Invention
The present invention relates to a fail-safe engine accelerator-throttle control. The exemplary embodiment detects operation of an accelerator pedal to control the opening of a throttle valve actuator, such as a motor, and controls the throttle valve opening by a predetermined fail-safe mode when an abnormality occurs.
2. Description of Related Art
Japanese unexamined patent application publication No. HEI 5-306636 discloses a similar type engine control. Such prior engine control detects operation of an accelerator pedal and accordingly controls the opening of a throttle valve during normal engine operation. When an abnormality occurs, a restricting member mechanically connected to the accelerator pedal is brought into contact with a cooperative member connected to the throttle valve in order to control the throttle valve opening. When an abnormality is detected, a motor is slowly operated to slowly bring the cooperative member into contact with the restricting member so that control smoothly enters a mechanical throttle control mode (limp-home mode).
However, if the abnormality includes the motor in, for example, shifting to a fail-safe engine control mode, smooth entry into the fail-safe mode fails because the motor cannot be properly controlled.